Add test to Comment.java

src/main/java/seedu/address/model/person/Comment.java

@@ -44,12 +44,12 @@ public boolean equals(Object other) {
         }
 
         // instanceof handles nulls
-        if (!(other instanceof Name)) {
+        if (!(other instanceof Comment)) {
             return false;
         }
 
-        Name otherName = (Name) other;
-        return fullComment.equals(otherName.fullName);
+        Comment otherComment = (Comment) other;
+        return fullComment.equals(otherComment.fullComment);
     }
 
     @Override

src/test/java/seedu/address/model/person/CommentTest.java

@@ -0,0 +1,61 @@
+package seedu.address.model.person;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static seedu.address.testutil.Assert.assertThrows;
+
+public class CommentTest {
+
+    @Test
+    public void constructor_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> new Comment(null));
+    }
+
+    @Test
+    public void constructor_invalidComment_throwsIllegalArgumentException() {
+        String invalidComment = "";
+        assertThrows(IllegalArgumentException.class, () -> new Comment(invalidComment));
+    }
+
+    @Test
+    public void isValidComment() {
+        // null name
+        assertThrows(NullPointerException.class, () -> Comment.isValidComment(null));
+
+        // invalid name
+        assertFalse(Comment.isValidComment("")); // empty string
+        assertFalse(Comment.isValidComment(" ")); // spaces only
+        assertFalse(Comment.isValidComment("^")); // only non-alphanumeric characters
+        assertFalse(Comment.isValidComment("prefer another set of cutlery*")); // contains non-alphanumeric characters
+
+        // valid name
+        assertTrue(Comment.isValidComment("prefer another set of cutlery")); // alphabets only
+        assertTrue(Comment.isValidComment("12345")); // numbers only
+        assertTrue(Comment.isValidComment("is 1st member")); // alphanumeric characters
+        assertTrue(Comment.isValidComment("Prefer Another Set of Cutlery")); // with capital letters
+        assertTrue(Comment.isValidComment("David Roger Jackson Ray Jr 2nd")); // long names
+    }
+
+    @Test
+    public void equals() {
+        Comment comment = new Comment("Valid Comment");
+
+        // same values -> returns true
+        assertTrue(comment.equals(new Comment("Valid Comment")));
+
+        // same object -> returns true
+        assertTrue(comment.equals(comment));
+
+        // null -> returns false
+        assertFalse(comment.equals(null));
+
+        // different types -> returns false
+        assertFalse(comment.equals(5.0f));
+
+        // different values -> returns false
+        assertFalse(comment.equals(new Comment("Other Valid Comment")));
+    }
+
+}